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Support and strata interaction at coal faces: technical note
80A and the critical depth bet~veen the 2 types of failure were identified. Top and skin resistance did not occur simultaneously. Using theoretical and experimental data. an equation to estimate the uplift capacity of anchors as a function of displacement was developed. The load displacement curves derived agree with laboratory and field results. 892236 Bousquet: winning battle of the bulge with innovative ground control World Min Equip V12, N6, June 1988, P22-25 The gold mine in Quebec has a mineralised zone in mainly volcanoclastic felsic rocks, and was originally mined by sublevel retreat to minimise ground movement. Support was by bolts and split sets. When instabilities due to the formation of a hanging wall wedge occurred, sub-level cut and fill was adopted as a remedial measure. Support is by bolts and cable lacing, and cemented mine waste is used as fill. The use of the Avoco method, named after an Irish copper mine where it originated, has allowed increased production at lower unit COSt.
892237 Sublevel stoping under high horizontal stress field at the Pyhasalmi Mine Lappalainen, P; Antikainen, J Proc 6th International Conference on Rock Mechan&s, Montreal, 30 Aug-lO Sept 1987 V2. P1063-I065. Puhl Rotterdam: A A Balkema. 1987 The Pyhasalmi Mine, Finland. has a stiff strong orcbody set in weak country rock under high horizontal stress, 30-70 MPa. Stability problems have been largely eliminated by pre-reinforcement with cable bolts, using a combination of'hedgehog' and "mandolin" designs, together with yielding pillars and stope shaping, sequential stoping techniques, and rapid placement of backfill. Excavation and bolting sequences for two stopes are illustrated. 892238 Development of a telescopic rockbolt Wang Daqing; Zheng Yutian Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 January 1988 P243-250. Publ London; IMM, 1988 The rigidity and ultimate elongation of a rock bolt should equal that of the surrounding rocks, since higher rigidity in the bolt leads to increased stress and failure of the bolt. The sleeve-tube-friction telescopic bolt has been developed to match the condition of the surrounding rock. The bolt consists of 2 interlocking tubes. When tensile forces reach the limiting frictional force, the bolt elongates. Tests indicate flexibility in primary support and rigidity in secondary support. Results of a successful trial in a tunnel are presented.
cable interface after fracture of the grout. Thus cable bolt failure is likely in the grout cable bond. The combined cable and split friction bolt support system has been successfully applied at Tonglushan mine. 892240 Finite element analysis and comparison of shaly mine roof support systems Unrug, K F; Nandy, S K Proc 5th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Tuscaloosa, 26-27 Oct 1987 PI 1-22. Publ Blacksburg: ~rginia Polytechnic and State Unirersity, 1987 Numerical analysis using the program ANSYS complemented field tests in examining options for roof support systems. Bedded clayey shale roof under massive sandstone, two bolt support designs, seasonal moisture variation, and moisture penetration through bolt holes were assumed. Shrinkage during drying out of clay minerals caused lowering of bolt tensions. Roof stability was seen to be sensitive to strata deformation. Clay swelling pressure increased loading on the bolts. Wooden header boards acted as soft inclusions in the system, and allowed larger deformations than steel straps. The analysis covers elastic deformation only. Later stages of deformation govern the mechanism of failure.
Direct rock support methods 892241 Support and strata interaction at coal faces: technical note Ke-Bin Zhang Int J Min Geol Engng V6, NI, March 1988, P85-88 The relation between the resistance of supports and roof convergence is a key issue in the study of strata pressure. The pressure regulating test has been designed to study the relation between yield load of supports and roof convergence. The test generates a curve which corresponds to cracking of roof strata, enabling general rules to be developed for roof strata movements and the definition of interactions between support and surrounding rocks. 892242 Preparation and transportation systems for cemented backfill Helms, W Min Sci Technol V7. N2. July 1988. P183-193 Cemented backfill has been successfully used in mining under various geotechnical conditions. Backfill technology, such as preparation of aggregrates, transportation and storage of aggregates and binding agents, and fill mixing, is described. Typical systems, such as cemented hydraulic sandfill, and cemented rock fill with stope filling from the surface, conveyor belt haulage, trackless transport or pneumatic stowing, are outlined. Planning of backfill systems is introduced.
892239 Application of a combined supporting technique with cable bolts and split friction bolts in fill stoping Xu Reiyong: Li Lixin Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 Januao' 1988 P263-267. Publ London." IMM. 1988
892243 Grouting Milan metro Mongilardi, E Worm Tunnlg VI, N3, Sept 1988, P222-224
The longhole cabling technique, including integration of anchoring and blasting in hollow bolts, is outlined, and the failure mechanics of a cable bolt investigated. A 2-d photoelastic model is used to study stress distribution. The results of this study, and those from pullout tests, indicate that stress is first concentrated at the rock-grout interface but shifts to grout-
Soil conditions in the area of the metro were determined using electronically instrumented rigs to record the main drilling parameters. These were used to derive specific energy and correlated with mean grain size to establish a classification by grain size. Grouting methods, particularly jet grouting, are described.
Grouting
~" 1989 Pergamon Press plc. Reproduction not permitted
892237 Sublevel stoping under high horizontal stress field at the Pyhasalmi Mine Lappalainen, P; Antikainen, J Proc 6th International Conference on Rock Mechan&s, Montreal, 30 Aug-lO Sept 1987 V2. P1063-I065. Puhl Rotterdam: A A Balkema. 1987 The Pyhasalmi Mine, Finland. has a stiff strong orcbody set in weak country rock under high horizontal stress, 30-70 MPa. Stability problems have been largely eliminated by pre-reinforcement with cable bolts, using a combination of'hedgehog' and "mandolin" designs, together with yielding pillars and stope shaping, sequential stoping techniques, and rapid placement of backfill. Excavation and bolting sequences for two stopes are illustrated. 892238 Development of a telescopic rockbolt Wang Daqing; Zheng Yutian Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 January 1988 P243-250. Publ London; IMM, 1988 The rigidity and ultimate elongation of a rock bolt should equal that of the surrounding rocks, since higher rigidity in the bolt leads to increased stress and failure of the bolt. The sleeve-tube-friction telescopic bolt has been developed to match the condition of the surrounding rock. The bolt consists of 2 interlocking tubes. When tensile forces reach the limiting frictional force, the bolt elongates. Tests indicate flexibility in primary support and rigidity in secondary support. Results of a successful trial in a tunnel are presented.
cable interface after fracture of the grout. Thus cable bolt failure is likely in the grout cable bond. The combined cable and split friction bolt support system has been successfully applied at Tonglushan mine. 892240 Finite element analysis and comparison of shaly mine roof support systems Unrug, K F; Nandy, S K Proc 5th Annual Workshop Generic Mineral Technology Center Mine Systems Design and Ground Control, Tuscaloosa, 26-27 Oct 1987 PI 1-22. Publ Blacksburg: ~rginia Polytechnic and State Unirersity, 1987 Numerical analysis using the program ANSYS complemented field tests in examining options for roof support systems. Bedded clayey shale roof under massive sandstone, two bolt support designs, seasonal moisture variation, and moisture penetration through bolt holes were assumed. Shrinkage during drying out of clay minerals caused lowering of bolt tensions. Roof stability was seen to be sensitive to strata deformation. Clay swelling pressure increased loading on the bolts. Wooden header boards acted as soft inclusions in the system, and allowed larger deformations than steel straps. The analysis covers elastic deformation only. Later stages of deformation govern the mechanism of failure.
Direct rock support methods 892241 Support and strata interaction at coal faces: technical note Ke-Bin Zhang Int J Min Geol Engng V6, NI, March 1988, P85-88 The relation between the resistance of supports and roof convergence is a key issue in the study of strata pressure. The pressure regulating test has been designed to study the relation between yield load of supports and roof convergence. The test generates a curve which corresponds to cracking of roof strata, enabling general rules to be developed for roof strata movements and the definition of interactions between support and surrounding rocks. 892242 Preparation and transportation systems for cemented backfill Helms, W Min Sci Technol V7. N2. July 1988. P183-193 Cemented backfill has been successfully used in mining under various geotechnical conditions. Backfill technology, such as preparation of aggregrates, transportation and storage of aggregates and binding agents, and fill mixing, is described. Typical systems, such as cemented hydraulic sandfill, and cemented rock fill with stope filling from the surface, conveyor belt haulage, trackless transport or pneumatic stowing, are outlined. Planning of backfill systems is introduced.
892239 Application of a combined supporting technique with cable bolts and split friction bolts in fill stoping Xu Reiyong: Li Lixin Proc CARE 88 (Conference on Applied Rock Engineering), Newcastle, 6-8 Januao' 1988 P263-267. Publ London." IMM. 1988
892243 Grouting Milan metro Mongilardi, E Worm Tunnlg VI, N3, Sept 1988, P222-224
The longhole cabling technique, including integration of anchoring and blasting in hollow bolts, is outlined, and the failure mechanics of a cable bolt investigated. A 2-d photoelastic model is used to study stress distribution. The results of this study, and those from pullout tests, indicate that stress is first concentrated at the rock-grout interface but shifts to grout-
Soil conditions in the area of the metro were determined using electronically instrumented rigs to record the main drilling parameters. These were used to derive specific energy and correlated with mean grain size to establish a classification by grain size. Grouting methods, particularly jet grouting, are described.
Grouting
~" 1989 Pergamon Press plc. Reproduction not permitted